Flow restrictor



J. O. HRUBY, JR

FLOW RESTRICTOR Filed Sept. 12, 1958 JNVENToR. 1;. cfo//v Heaay, rf?.

rraeA/fys.

United States Patent() FLOW RESTRICTOR John 0. Hruby, Jr., Burbank,Calif., amignor to Rain'Jet Corporation, Burbank, Calif., a corporationof California Filed Sept. 12, 1958, Ser. No. 769,686

7 Claims. (Cl. 251-216) This invention relates to restrictors forcontrolling flow of uids through tubular conduits.

While the invention may be employed advantageously for various conduitinstallations, including, for example, heating systems `and overheadsprinkler systems, I have chosen to illustrate and describe theinvention as the same may be embodied in a lawn sprinkler system, forwhen so described the advantages of the invention become readilyapparent.

In the installation of conventional lawn sprinkler systems, a pipeleading from a waterline is laid into the ground and a plurality ofshort risers are connected to it for attaching springler heads to thepipe. The flow restrictors of this invention are adapted to be mountedwithin or in alignment with such risers thereby to enable control of thesize of sprays from the sprinkler heads.

It is a general object of this invention to provide an improvedrestrictor which may be adjusted easily when positioned in a conduit toobtain a desired rate of flow in the conduit.

Another object of this invention is to provide a restrictor of the abovementioned character which is simple in construction, easy to install,eioient in operation, and of relatively low cost.

Further objects and advantages of this invention will appear in thefollowing part of this specication wherein the details of constructionand mode of operation of a preferred embodiment are described withreference to the accompanying drawing, in which:

Fig. 1 is a side elevation, with certain parts being shown in centralVertical section, of a portion of a lawn sprinkler system having arestrictor of this invention contained therein;

Fig. 2 is a central vertical section through the restrictor taken alongline 2 2 of Fig. l

Fig. 3 is another central vertical section through the restrictor takenperpendicular to the section of Fig. 2; and

Fig. 4 is a cross section taken on line 4 4 of Fig. 3.

Referring to the drawing in greater detail, there is shown a pipe and apipe-T 11 of a lawn sprinkler system. Extending vertically above thepipe-T is a riser pipe 12 having a sprinkler head 13 mounted upon theupper end thereof. The sprinkler head is shown for illustration purposesonly, and may be of `the type described in United States Letters PatentNo. 2,639,191, issued May 19, 1953.

A restrictor embodying this invention and designated, generally, byreference numeral 16 is positioned in the pipe-T 11 as an extension ofthe riser 12, the illustrated restrictor constituting the upstream(lower) end of the riser. The restrictor comprises a tubular body 18having a male end portion 19 which is externally screw-threaded forengagement with internal screw threads 20 in the pipe-T 11. The lowerannular end surface of the body is designated by numeral 21.

A downstream (upper) end portion`22 of the restrictor body comprises afemale tting which is internally screwr1ice threaded at 23 for receivingthe lower end of the pipe 12. From the screw threads 23, the inside ofthe body is of reduced diameter to define an inclined annular shoulder24 and a cylindrical inside wall 25 extending coaxially in the body.Near the upstream (lower) end of the body there is a chamfered annularshoulder 26 extending inwardly from the lower end of the cylindricalwall 25 to make the inside of the body of still smaller inside diameterin an internally screw-threaded end portion or flange 27.

The body receives a solid plug 29 comprising a cylindrical head portion30 and a cylindrical stem portion 31. The lower end face of the plug isdesignated by reference numeral 32 and its upper surface by numeral 33.Numeral 34 designates the cylindrical side walls of the head portion.The stem portion is externally screw-threaded throughout the lengththereof for mating with the screw threads in the inside flange 27. Afrusto-conical shoulder 35 defines the upper end of the stem portion ofthe plug and the lower end of the head portion of the plug and seatsupon the chamfered shoulder 26 in the body when the plug is turned downin the body to its lowermost position.

The plug is preferably formed from relatively hard plastics, e.g. nylon,whereby the same has resiliency. The cylindrical side walls of the headportion of the plug are made to -a diameter such that the head portionwill iit slidably but tightly against the cylindrical inside wall 25 ofthe body to prevent unintended rotation of the plug in the body.

A diagonally extending groove 38 is formed in the head portion of theplug and is open to the upper surface 33 for accommodating the tool endof a screwdriver (not shown) for turning the plug in the restrictorbody. Such groove or slot 38 preferably extends at least down to thelevel of the shoulder 35 thus dividing the head portion to increase theresiliency thereof for fitting down tight in the cylindrical wall 25 ofthe body.

The plug has two longitudinally extending grooves 40 and 41 formed inthe stem portion thereof, open in the outside surface of the stemportion and being continuous with the head groove 38 whereby they leavea rib 42 between them. These stem grooves terminate in a rounded endportion at 43 above the lower end face 32 of the plug. The stem and itsgrooves 40 and 41 are of a length such that the lower end portion of thestem below the ends 43 of the stem grooves will be engaged in the screwthreads of the inside llange 27 of the body before the cylindrical sidewalls of the head portion engage in the cylindrical inside wall 25 ofthe body, as appears in Fig. 3 of the drawing. As the plug is turneddown in the body, the plug head becomes received within the cylindricalwall 25 to bind the plug in the body. Further turning of the plug willcause the lower ends of the grooves 40 and 41 to become exposed beyondthe lower end 21 of the body, thereby to provide passageways through theplug. The size of openings of such passageways is controlled byrot-ation of the plug in the body resulting in increasing or decreasingthe extent to which the stem grooves are exposed beyond the lower end ofthe body.

The restrictors of this invention may be installed in a lawn sprinklersystem and adjusted to equalize the spray from the several sprinklerheads of the sprinkler system or to cause one sprinkler head to cover alarger or smaller area than others as desired and as explained in UnitedStates Letters Patent No. 2,810,607.

While the instant invention has been shown and described herein, in whatis conceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of theinvention, which is therefore not to be limited to the details disclosedherein, but is to bc accorded the full scope of the claims.

What I claim is:

1. A flow restrictor for a conduit comprising an openended tubular bodyadapted to deiine a, section of the conduit, the body having oppositeends which deiine end openings of ther body, respectively, a cylindricalinside wall portion of circular cross, section, and an inwardlyextending annular shoulder portion spaced axiallyv from one end of thebody, said shoulder portion being internally screw-threaded; a plughaving a head portion and a stem portion and an end surface for the headportion and an end surface for the stem portion, said end surfaces beingopposite end surfaces ofthe plug, the head portion having a cylindricalside wall extending coaxially of theplug and being of just slightlydiameter than the stem portion such as to be tightly slidable axially insaidinside wall, the stem portion being externally screw-threaded formating with` the screw threads of said shoulder portion, the plug havinga longitudinally extending groove formed therein, said groove being openin the head end surface of the plug and open in the side walls of thehead and stern portions and terminating short of the stem end surface ofthe plug, whereby as the plug is rotated in the body said groove becomesexposed in the side wall of the stern portion beyond said shoulderportion and said head portion lits tightly inthe cylindrical wallportion of the body to prevent unintended rotation of the plug in thebody, and the groove provides for uid flow to within the body opening insaid one end of the body.

2. A flow restrictor according to claim 1 in which said plug is formedof nylon.

3. A flow restrictor for a condu-it comprising an openended tubular bodyadapted to be mounted in the conduit and having an upstream end surface,a downstream end surface, a cylindrical inside Wall portion of circularcross section disposed coaxially of the body and inte-rmediate its ends,and an inwardly extending annular shoulder portion proximate itsupstream end, said shoulder portion being internally screw-threaded; anelongate plug having a downstream end, an upstream end, a stem. portionextending from the upstream end of the plug, and a head portion at thedownstream end of the plug, the head portion having a cylindrical sidewall extending coaxially of the plug and being of just slightly greaterdiameter than the stem portion such as to be tightly slidable axially insaid inside wall, the stem portion being externally screw-threaded format-ing with the screw threads of said shoulder portion, lthe plughaving a longitudinally extending groove formed therein, said groovebeing open in the downstream end surface of the plug and open in theside walls of the head and stem portions and terminating short of theupstream end surface of the plug, whereby as the plug is rotated in thebody to move in an upstream direction with respect to the body saidgroove becomes exposed beyond said shoulder portion and said headportion tits tightly in the cylindrical wall of the body to preventunintended rotation of the plug in the body, and the groove provides forow of fluid to within the downstream end portion of the body.

4. A flow restrictor for a conduit comprising an openended tubular bodyadapted to be mounted in the conduit Iand having an upstream endsurf-ace, a downstream end surface, a cylindrical inside wall portion ofcircular cross section disposed coaxially of the body and intermediateits ends, and an inwardly extending annular shoulder portion proximateits upstream end, said shoulder portion being internally screw-threaded;`an elongate plug having a downstream end, an upstream end, a stemportion extending from the upstream end of the plug, and a head portionat the downstream end of the plug, the head portion having a cylindricalside wall extending coaxially of the plug and being of just slightlygreater diameter than the stern portion such as to be tightly slidableaxially in said inside wall, the stem portion being externallyscrewthreaded for mating with the screw threads of said shoulderportion, the plug having two diametrically opposed grooves forrnedtherein and extending longitudinally of the plug, said grooves beingopen in the downstream end surface of the plug and open in the sidewalls of the head and stern portions and terminating short of theupstream end surface of the plug, ywhereby as the plug is rotated in thebody to move in an upstream direction with respect to the body saidgrooves become exposed beyond said shoulder portion and said headport-ion iits tightly in the cylindrical wall of the body to preventunintended rotation of the plug in the body and said grooves provide forflow of lluid to within the downstream end portion of the body.

5. A restrictor according to cla-im 4 in which said grooves terminate atan equal distance from the upstream end surface of the plug.

6. A restrictor according to claim 4 and comprising a diametricallyextending slot formed in the downstream end surface of the plug andbeing continuous with said grooves.

7. A restrictor according to claim 6 in which said slot extends to adepth substantially equal to the axial length of the side wall of saidhead portion.

References Cited in the le of this patent UNITED STATES PATENTS1,132,175 Filczer Mar. 16, 1915 1,857,940 Chouinard et al May l0, 19322,095,372 Slavin et al Oct. 12, 1937 2,697,582 Grosch Dec. 21, 19542,865,596 Monning Dec. 23, 1958

